


Just keep swimming.

by RussianSunflower3



Category: Haikyuu!!
Genre: Birthday Fluff, Crack Treated Seriously, Fish, Fluff and Humor, Gen, Godzilla - Freeform, Happy Birthday Iwaizumi!, Magic, Seijou 4 as family, Sorry for turning you into a fish, Team as Family, Tosakin goldfish
Language: English
Status: Completed
Published: 2019-06-10
Updated: 2019-06-10
Packaged: 2020-04-23 21:50:03
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,464
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19159654
Author URL: https://archiveofourown.org/users/RussianSunflower3/pseuds/RussianSunflower3
Summary: The last thing Iwaizumi expected for his birthday was to find out magic was real.But he did.Because somehow, his friends have managed to turn him into a fish.Well.Fintastic.





	Just keep swimming.

Of all the things he had expected to happen on birthday, turning into a fish and being chucked into his best friend’s fruit juice was not one of them.

“Oh my gosh, Iwa-chan, I’m _so_ sorry! This is literally the best any of us can offer!” Oikawa’s face is distorted through the cylinder glass, but it’s clear he’s a mix of mortified and distressed. The angry little fish swims in a circle, flicking his tail to send a small stream of bubbles towards Oikawa.

Iwaizumi Hajime is _not_ happy to be in this situation. 

He’s even less happy that he can hear rapturous laughter coming from Hanamaki and Matsukawa, as far-off and distorted as it may sound. Puffing out his little fish cheeks, Iwaizumi spins around and charges at them, forgetting one important thing.

_TUP!_

Ah, yes. He’s in a glass. A glass of grapefruit juice. _Oikawa’s_ glass of grapefruit juice.

“I- Iwa-chan?!” The glass shakes as Oikawa lifts it to his face, desperately looking in to see the tiny, **furious** fish repeatedly slam into the glass, in the direction of Hanamaki and Matsukawa. He forces a nervous, high-pitched giggle, though it’s weak and fades halfway.

“I’m pretty sure that’s Iwa-chan promising to murder you both once he’s out of the glass…” Much to Oikawa’s surprise, as well as the terrible twos delight, Iwaizumi gestures slicing a throat with his fin.

“He can understand us! Oh, this is _divine_! This is wonderful!” 

“What part of this is wonderful, Makki?!?! My best friend is a fish!!!!” Cackling harder, Hanamaki flops backwards so he’s lying on the floor, clutching his stomach through wheezes. 

“If- If we didn’t know that was Iwaizumi, that sentence would sound so _stupid_! Who has a fish for a best friend!? Ahahaha!” 

“Me, apparently. How did you even manage this?!” Since Hanamaki is out of action, laughing too hard to even sit up, Matsukawa answers by nudging the book they’d brought Iwaizumi closer to Oikawa. Some kind of teal powder that glitters like sunlight and ripples like the oceans moves around on the page like a gelatin droplet.

“Don’t touch that stuff. Iwaizumi did, and, well, just look at him.” Oikawa does. A grumpy fish stares back. He even has the ‘angry eyebrows’ pattern on his skin. Uh, scales…? Sighing with a vague tone of disappointment, Oikawa levels the other two with a flat glare.

“Where did you get the book?” Helpfully, Matsukawa shrugs. Hanamaki is still no help at all, having laughed so hard that he now gasps for breath, until he glances over at the grapefruit juice, is greeted by what he _assumes_ is supposed to be a middle finger - it’s hard to tell when it’s a fin instead of fingers - and bursts into giggles once again. 

Matsukawa’s lips twitch upwards in amusement and he leans over to pat Hanamaki’s knee, not only reminding him to breathe, but also reassurance. Because by god, Oikawa looks like he’s ready to murder them both, and Iwaizumi looks like he’s plotting vengeance. It’s an unnerving expression for a fish.

“What am I supposed to do, Mattsun? Iwa-chan is a fish, and Makki is clearly only going to hinder any way of getting him back to normal.”

“Hey!” The jibe instantly sobers Hanamaki up, throwing himself into a sitting position and glaring back at Oikawa. His glare quickly morphs into concern.

“Umm… Is grapefruit juice really suitable for fish…? ‘Cus Iwaizumi looks like he might be, uh… Suffocating?” Oikawa whips his gaze from Hanamaki to the fish in his fruit juice, and Matsukawa snaps his head up from reading the book.

Sure enough, in the grapefruit juice, Iwaizumi is starting to slow down, struggling to reach the surface for some air. He _can_ breathe underwater now (which is pretty cool, he’ll admit that much), but the juice is **burning his gills**.

It’s grapefruit, for god's sake! 

Matsukawa bolts for the kitchen, wobbling a bit on legs that have become numb from where they’ve been crossed, off to fetch some fresh, clean water. Hanamaki snaps into action, reaching into the cup and gently raising the fish to the top of the glass, ready to transfer him over as soon as Matsukawa comes back.

With nothing else he can do, Oikawa holds his breath and nibbles his bottom lip in worry, his hands shaking minimally as both of them clutch the glass with desperation.

“Hope you don’t mind I stole this from your cupboards.” Matsukawa slides back in with a mixing bowl full of water, spilling the tiniest bit as he skids to his knees next to Oikawa. In one swift move, Hanamaki moves Iwaizumi from the glass to the bowl, a huge improvement in both water quality and size.

He flicks his tail in thanks, pauses for a moment, and then jumps out of the water to splash Oikawa in the face. With droplets of water running off his startles face, Oikawa blinks twice. Then, he laughs a little.

“Geez, even as a fish, Iwa-chan can knock some sense into me~.”

“He sure has a talent, huh.” A couple of self-assured bubbles pop on the surface of the bowl water. For a moment, all the three who are still currently human can do is look down at their friend, attempting to figure out what the _hell_ they’re going to do.

“Well. On the bright side, the book said this only lasts 12 hours.”

“I hate to dash your spirits, Mattsun, but that’s still 12 hours we could accidentally kill Iwa-chan. None of us know the first thing about looking after fish! Especially not-... Whatever species he is!” Hanamaki perks up.

“Hey, didn’t Kindaichi say he had tropical fish once? We could ask for help.” Three looks that can only be described as ‘What in the fresh fuck’ are sent his way, which is particularly disconcerting in Iwaizumi’s case. As he realises Hanamaki is serious, Iwaizumi frantically tries to shake his head - which is unfortunately not on a neck - to get his point across.

His _one_ saving grace in terms of embarrassing himself is that none of their underclassmen are here. This little birthday gathering was for the four best friends only, a decision that had turned out rather lucky.

Or not. Not- Lucky. Just… He was thankful no-one else was here to witness his fall into fishdom. It was _mortifying_.

Cool, but mortifying.

“What on _earth_ makes you think he’s going to believe; ‘Oh, Iwa-chan was turned into a fish because Makki and Mattsun brought some magically infused book.’ In what universe does that make sense?!?!”

“This one, apparently.” Iwaizumi splashes again, this time sending water sloshing over the edge of the bowl and onto Hanamaki’s lap.

“Gah! What was that for?!” Oikawa’s brow furrows as he watches Iwaizumi dash back and forth in the bowl, just like how he would pace on two human legs when he needed time to himself but was suitably in distress.

“I don’t think he likes that, Makki…”

“Do you have any better ideas?” Silence. Matsukawa scratches at his chin in thought.

“Hmm… Guess we don’t have to clarify that the fish is Iwaizumi specifically.” 

“That’s… True. What’s your thought on that?” Iwaizumi stops swimming back and forth, and instead stares straight up at Oikawa. He does - with great joy at his success - a somersault in the water.

Oikawa barks a laugh at Iwaizumi’s grand communication skills, whilst Matsukawa snickers at the acrobatics. He’s never seen a fish do one before. He does feel a _little_ guilty for being the one who got Iwaizumi into this situation in the first place, but, well, it’s happened and they’ve just got to deal with that.

It’s not like it’s permanent anyways. If it’s going to wear off in 12 hours, they may as well have their fun with it. 

“I’m gonna video call the kid so he can tell us what to do. We all alright with that?” Receiving three okays, one of them non-verbal for obvious, fishy reasons, Hanamaki continuously requests video calls on LINE until Kindaichi picks up.

_“Is everything okay, Senpai?”_ His expression is concerned, but also tired, and his hair is askew like he’s been lying on his side. Hanamaki barely represses a snort at the dishevelled appearance, including a trail of saliva down his chin and sleep crust in the corners of his eyes.

“You’re sleeping at 6 in the afternoon?”

“Wha-! Makki, apologise for waking him up!”

“Aww, c’mon! Practice didn’t burn us out that much!” Before Hanamaki can start squabbling with Oikawa, the sound of a squeaky yawn breaks the tension, and Hanamaki watches as Kindaichi on screen rubs the sleep away from the edges of his eyes.

_“In case you’ve forgotten, I have to get all the way to Fukuoka, have an appendectomy, and then come back all before lessons start.”_

“... Oops.” Hanamaki sheepishly grins, hoping it’s enough to get his apology across whilst Matsukawa shuffles round to sit next to him, leaning in so he’s visible on Kindaichi’s end too.

“You doing okay? It’s kinda unfair your mother insists on just that one hospital…”

_“Honestly? I’m more terrified about the surgery than annoyed by the travel. S’good thing practice is only casual until April. I’ll be out of action for 4 weeks. ...As long as there’s no complications and I **really** hope I don’t die.” _

“You’ll do great, Kin-chan. We’ll have to arrange a game with Karasuno for when you can join in again!” A warm, tired chuckle comes from the screen, and Oikawa’s grip on Iwaizumi’s bowl relaxes a little. He’s too tense, but welcome conversation like this eases his nerves.

_“Sounds good. So, why are ringing me, Hanamaki-Senpai?”_ For a moment, Hanamaki forget, blinking rapidly. And then, he jolts up straighter, grinning as usual.

“Oh yeah! You have fish, right?!” The screen briefly moves to display full tanks of fish. Not one, not two, but _three_ tanks, each brimming with life.

_“The tropical tank; Angel fish, neon tetras, and rasbora. The Caribbean tank; Hamlets, seahorses, and Damselfish. And the freshwater tank; Danios, Mollies, and Platies.”_

“Oh, sweet!!!!” Whilst Hanamaki gawps enthusiastically over the fish display, Kindaichi obviously proud of the reaction despite his weariness, Matsukawa presses the button to turn the camera around.

“So what type of fish is this?” 

“And please help because we have no idea how to look after Iwa-chan…’s fish! Iwa-chan’s fish. Birthday present.” Oikawa almost sweatdrops comically as the two now behind the phone camera give him raised eyebrows and deadpan stares. Even Iwaizumi stops swimming for a second, sinking to the bottom of the bowl in disbelief at Oikawa’s slip up.

Wise on the court, he is. Wise off the court, he is not. Smart, yes, but not wise.

_“Oh- Oh my god. Oh my GOD!!!! That’s- Where did you find it?!?!”_ The response is much bigger than Oikawa would have expected, and he blinks down at Iwaizumi, switches his gaze to Kindaichi pretty much freaking out in a good way, and then back to Iwaizumi.

“Uh… Some shady, back alley pet shop… He only came with a plastic bag?” It’s a lie for certain, but Oikawa delivers it smoothly, and Kindaichi’s face falls into a frown through the screen.

_“Yeah, there’s a saddening amount of those nowadays. But that!!! That’s an awesome fish!!! Definitely a Tosakin goldfish, but that **colouration**!!! Oh geez, you may just have a super rare fish right there.”_

“Colouration…?” Peering into the bow, Oikawa doesn’t spot anything out of the ordinary with Iwaizumi in fish form. It looks just like… Uh… Iwaizumi in fish form. Black like his hair, splotches of teal and white like their signature Aobajousai colours, and the occasional scale of green, like his human eye colour.

_“Yeah! I’ve only ever seen Tosakin’s in orange and white or gold and white, maybe with a speckle of black, but **never** with that much black, and **absolutely NEVER** with such a vivid blue!!! That’s one hell of an incredible goldfish!”_

If a fish could ever look proud, it would be this one in a baking bowl right now. Iwaizumi absolutely preens under the praise. It’s pretty bad that he’s ended up in this situation, but being a fish in itself is pretty cool, being flattered like this is a bonus. He even tries to puff out his chest, despite the lack of lungs.

Or chest. He’s literally face to belly to tail now.

_“I have a spare old tank you could use? It’s not exactly state of the art, but it’s definitely enough for one single fish. I’ll bring some aquatic plants, filters, and gravel too. Cus, uh, if that’s all you’ve got for that fish… It’s really not enough.”_

“This is indeed all we have.” There’s a somewhat disappointed sigh from the other end of the video call which amazingly makes all three of them feel worse about the situation. Hanamaki quickly flips the phone around.

“Uh, but! Don’t put yourself out of your way. Matsukawa and I can come pick it up, you take a nap or something.”

_“Do you know how to set it up?”_ The ensuing silence is all Kindaichi needs to know, so he tells them to expect him soon, and ends the call. With a sigh, Oikawa places the bowl on the floor and peers in at Iwaizumi.

“I hope you’re proud of yourself, Iwa-chan.” Iwaizumi whirls around on him, gawping at the _audacity_ of Oikawa implying this is his fault! Clearly, Hanamaki and Matsukawa are at fault here, so why is _he_ being blamed?! 

It’s only when he sees the tiny smirk on Oikawa’s lips that he realises Oikawa is joking. Still, for good effect, he frowns as much as his fishy.. - Lips? Are they lips? Do fish even have lips? - lips will allow, and splashes water up at Oikawa with one flick of his elegant tail fin. 

Huh. He could get used to this.

“Stop doing that! You have limited water in your bowl!” Iwaizumi waves a fin towards the kitchen, wordlessly communicating ‘so get more’, and Oikawa’s eyebrow twitches because _damn it_ , he can flawlessly imagine the bored, factual way Iwaizumi would sound saying it.

“I can’t believe I’m talking to a fish.” Matsukawa snorts as he scrolls through his phone, sliding his vision up to Oikawa without moving his head.

“Technically, that fish is your best friend-”

“Again, sounds hilarious to anyone who doesn’t know the situation.”

“- and we’ve seen you do much stranger.” Hanamaki’s unhelpful input mid-sentence is paired with a grin, that only grows into a laugh when he thinks about some of those strange things Matsukawa might be implying.

“Like the time he stared Coach in the eye, removed his shoes, threw one in the rafters and the other at Yahaba, then proclaimed that he had no soul because he had no ‘sole’? C l a s s i c.” Oikawa puffs his chest out proudly.

“Of course! That’s what he gets for ever implying I might be on the same team as Tobio-chan, and to ‘put my soul’ into training younger setters.” Iwaizumi would very much like to remind Oikawa that he probably will end up on the same team as Kageyama. He’d very much like to lecture Oikawa about how shitty he’s behaving towards Kageyama, when their differences should have settled by now.

He’d like to tell Oikawa that disliking Kageyama was fine, but this level of animosity towards him was unjust.

Iwaizumi would _like_ to say all that, but he can’t. Because he’s a fish. A goddamn goldfish, on his own birthday, because two idiots brought a mysterious book. A few angry bubbles escape and pop on the surface of the water, unheard as the three who are luckily still human converse and laugh.

“ - going to do for tea? I mean, do we give him fish flakes, or actual human food?” 

“Google says worms, peas, and courgette are safe for goldfish in an emergency situation.”

“I value your opinion, Matsukawa, but Iwaizumi already wants to kill us. I’m not going to make that worse by trying to feed him worms.” Horrified at the prospect of having _worms_ thrown into his little baking bowl, Iwaizumi splashes the surface of the water, swimming around in what he hopes is an ‘X’ formation.

“So… Peas and courgette?” Iwaizumi glares as best he can at Matsukawa. His birthday is already going terribly, he’s not going to miss his special birthday meal and cake on top of that. He never asked to be a fish! Eyebrows raised in surprise at the menacing expression, Matsukawa holds up his hands in mock surrender.

“Okay, okay, just trying not to kill you, bud.”

“There’s gotta be something else, Mattsun. Like, what do wild goldfish eat?”

“Bugs.” Oikawa pulls a face of disgust, very much mirrored by Iwaizumi who hopes to high heaven that they don’t try feeding him bugs, thank you very much, just as Hanamaki slaps his hands on the floor like he’s had a breakthrough.

“What about seaweed?! Or- Or smaller fish, or shrimp? Hell, we could even make mini sashimi or sushi for him!” Blinking in surprise at the sensible suggestion, Oikawa turns to the baking bowl, gazing in at Iwaizumi with a questioning expression. Even Iwaizumi seems to be considering it.

Sushi is… It’s not his favourite, but better than being fed worms and bugs. It might be the only option. Anything not safe for goldfish could kill him, potentially, and anything disgusting would incite his rage to kill the others.

Eventually, he bobs his body like he’s nodding and a couple of bubbles pop on the surface where he’s blown them. 

“Sushi it is!” Hanamaki happily trots through to the kitchen. He’s the best chef out of any of them, no matter what it is he’s trying to make. Matsukawa, on the other hand, is absolutely terrible at cooking and therefore banned from the kitchen.

That’s not a problem, because he’s currently leaning over the baking bowl, intrigued in Iwaizumi’s fishy communication skills. Literally fishy. Iwaizumi isn’t quite sure how to tell him that he can see right up his nostrils though.

With nothing else to do but wait, Oikawa adorns a pair of rather fetching rubber gloves and starts inspecting the book, specifically the page Iwaizumi had incidentally opened it to after unwrapping it, which had… Turned him into a fish.

Out of curiosity, Oikawa flicks the page over to see what other mysteries this book may hold.

“...Huh.” Matsukawa peers over at him at the bland humm, raising an eyebrow very slightly.

“We should probably never let Iwa-chan see this page. He’ll be _furious_ he didn’t get this one.” Well. That’s piqued his interest. Matsukawa leans over, making sure to push a curious little fish back down in his ‘bowl’.

His dark eyes widen.

“Oh yeah. Shit. Let’s, uh, let’s just rip that page out.” 

“We can’t _rip_ it out! Let’s just- deface it or something! Grab the felt tips from that drawer over there.” Iwaizumi slaps his fins on the surface of the water, demanding to know what they’re talking about. For a moment, all three just stare at each other.

Iwaizumi glares. His little fish ‘eyebrows’ make his glare all the more disconcerting. 

Oikawa flips the book around for Iwaizumi to see the page.

_‘A marine iguana?!’_

“Oikawa, why would you do that? Now he’s gonna go full Godzilla on our asses once he’s human again.”

“Trust me, Mattsun, the punishment would have been worse if we hid it first and he - undoubtedly - found out.” The livid splashing inside the bowl, almost like a tempest had whipped up the surface, doesn’t encourage Matsukawa to see it Oikawa’s way. 

“Well… You’ve been his friend longest, so I can trust that. … I guess~.” His teasing add-on earns him a punch to the shoulder, and he laughs. It’s a deep, genuine, but quiet laugh. Quiet enough that the knock on the front door can be heard under it.

“I’ll get it.” As Matsukawa gets up to answer the door, Oikawa very carefully closes the book, tucks some of the wrapping paper back over it, and slides it under the sofa so no-one accidentally gets more magic stuff on them.

Because that’s the only reason Oikawa can think of for Iwaizumi becoming a fish. Magic. Never trust inconspicuous books with strange liquid-like powders on each page.

“- otherwise the change in temperature could shock the fish into-! Hi, Oikawa-senpai!” Kindaichi looks a lot more awake now than he did over the video call, although his arms are laden down by a large tank and bags of what Oikawa supposes are supplies. Matsukawa must have taken some at the door, because he carries a tub-like thingy of expensive looking equipment.

“Hi, Kin-chan~. Looks like you brought _waaaaay_ more than we needed. That tank is half the size of my bathtub!”

“Oh, uh, not really? This is the bare minimum.” Setting the stuff carefully down on the sofa, Kindaichi stretches out his shoulders before kneeling down to take a good look at the goldfish in the baking bowl.

“Aww, it’s so cute! Definitely a back-street breeder though, not an official one.”

“Hmm? How can you tell?” As Iwaizumi does a couple of loops to follow the finger Kindaichi presses just on the surface of the bowl - mostly because it keeps his observer happy - Oikawa peers into the bowl too.

“Ah, see how this side of the tailfin here doesn’t have a perfect twist? And the little blotch of green scales on one side but grey on the other? Tosakin breeders will cull any fish that aren’t perfectly symmetrical before they grow up. In a way, this guy was lucky he came from a shady background.”

“You- You mean they’ll just _kill_ fish? Because they’re not perfect?” Matsukawa’s face pales just a little. It’s something he’s never thought about, but now Iwaizumi is _stuck_ as a fish, these things are relevant. Even if Iwaizumi is safe in their hands.

“Cull, yes. I don’t personally agree with it, but it does mean less competition for the other fry.” There’s a beat of silence filled only by the background bustling of the kitchen as Hanamaki does… Something… In there.

“Wow. The fish world is cruel.” That gets a laugh out of Kindaichi, who moves automatically and fluidly as he sets up the tank and all its additions on the desk Oikawa casually directs him towards. They only need it for a few hours anyways.

Iwaizumi keeps swimming to the surface of the bowl to watch in fascination, diving back down for water to filter over his gills, and then resurface. Watching Oikawa and Matsukawa try to help set up the fish tank is _hilarious_.

It’s also worrying because that’s where he’s going to live for a little bit. He’d quite like it to _not_ be a death-trap. 

“There! Hopefully, Iwa-chan loves it!” Kindaichi laughs as he reaches into the last bag, pulling out a couple of decorative pieces. One of them looks like a godzilla figurine and Iwaizumi goes _wild_. He almost splashes himself out of the bowl!

“I thought that since it’s for Iwaizumi-senpai, he’d appreciate this more than the stereotypical diver guy~.” 

“Kin-chan, I think you just made his birthday worth it.” Confused, the first year looks around a little bit.

“Where actually is Senpai? I mean, this is his house, so…” 

“He’s out for birthday lunch with his mother. We’re setting this up for when he gets back!” It’s a quickly thought-up lie, but Oikawa delivers it as smoothly as he commands the court, leaving no room for doubt. Iwaizumi’s mother is, as a matter of fact, having a sleepover at the Oikawa house, so the boys can mess around and celebrate.

“In that case, I wanted to ask a little bit about the surprise party tomorrow-... What? Did I say something wrong?” The only word to describe Oikawa and Matsukawa’s face are _aghast_. The surprise party they’d been planning for Iwaizumi had been kept secret for _**seven months**_.

“Well… It’s not a secret anymore.” Matsukawa tries to ignore the smug splash of Iwaizumi’s tail against the surface of his bowl.

“It- It’s not?” Oikawa immediately jabs his elbow into Matsukawa’s ribs.

“Mattsun gave it away yesterday! He asked something about… Uhh…” Oikawa trails off, blankly blinking as his thoughts grind to a halt. Iwaizumi rolls his fish eyes. Sometimes, he swears his three friends have a single brain call shared between them, and Oikawa’s turn just timed out.

“Catering. I want my fucking cheese-filled hamburgers.” If Kindaichi notices that both of his senpai have broken out in a cold sweat, he doesn’t mention it. Iwaizumi is rather thankful that he just accepts the lie with a nod, because it’s cringy watching his friends flail for answers.

Although he’s even more thankful that he knows about the surprise party now. He _knew_ they were up to something.

“In any case, I think I’m going to make a move now. I still need to rest before we leave at 2 in the morning, if I want any hope of getting back for school.”

“Ow, fuck. You _can_ take a day off, y’know.” Kindaichi gives Matsukawa this expression that can only be described as cynical matched with ‘what the fuck’ before he shakes it off with a slight frown.

“College prep classes are going hardcore as we get to the end of the year. Kunimi and I have mock placement test in the afternoon.” A hiss of sympathetic pain escapes Matsukawa’s gritted teeth. He can remember how stressed Oikawa and Iwaizumi were at the end of their first and second years.

Mock placement tests must have been the reason. He shivers in cold dread at the thought that they’ll be doing the official college placements as soon as they’ve graduated. Oh god, if Iwaizumi was somehow going to spare their lives after this fish incident, Hanamaki and Matsukawa were going to have to go into hiding.

“Good- uh, Good luck?” Again, Oikawa elbows him in the ribs, before relaxing and smiling reassuringly.

“Don’t worry, you’re going to do great. Go home! Rest! And text us as soon as you’re on your way back! We’ll make arrangements to meet up for lunch.”

“O- Okay~!” Beaming excitedly, Kindaichi runs through a few more pointers on the tank, and transferring the Tosakin into it, before he’s waved off at the door and heads home. The whole room feels a little calmer, a little warmer.

Oikawa slumps into the sofa, kicking his legs in the air as he wraps his arms around a cushion, pulling it into his chest. Matsukawa simply sinks to the floor, cross-legged as he pats around for the remote which he _knows_ he left here somewhere…

“Makki’s maki rolls, at your service~!” Hanamaki swings around the kitchen door frame, a platter of beautifully presented sushi on one hand. It’s not the traditional nigiri or sashimi, but rather tiny little maki rolls of carefully diced fillings, a single layer of boiled rice, all wrapped in nori seaweed.

“A culinary delight, even in your fishy plight!” In Iwaizumi’s defence, Hanamaki well deserves wet feet for that remark, as he splashes a little of the remaining water over Hanamaki’s feet. Oikawa reaches an arm down to poke the fish back into the now half empty bowl.

“Iwa-chan, stop doing that! You’re making my carpet soaked, you’re running out of water to swim and breathe in, and we have to wait until it reaches the same temperature as the tank!” Iwaizumi guiltily lets himself sink to the bottom of the baking bowl, letting out a few bubbles of apology.

“Hey, what about my feet, huh? Do I not matter to you, Oikawa?”

“Not when you’re the catalyst for this entire event. My best friend! Is a _fish_! A fucking fish, Makki! I know you’re to blame because Mattsun has no idea where the book came from!”

“Wha-?! He’s the one who suggested some kind of cool book because Iwaizumi likes all that mystery and mythology stuff!” 

“Dude, don’t pin the blame on me. I told you to check the bookstore on the mainstreet. _You’re_ the one who went to some shady antiques shop, or as you described it, a ‘wonderland of lost opportunities’. One of which, ended up with Iwaizumi as a fish.”

"Oh yeah? Well maybe, just _maybe_ , you could have put some actual fucking _**effort**_ into helping me pick out a present!”

“I was looking after the twins! You think I wanted to clean up two seven year old’s explosive diarrhea and vomit for two days in a row?!”

“Makki! Mattsun! _Enough_!” All it takes is a sharp bark from Oikawa in his captain voice to silence the duo, and they realise that maybe they’ve gone a step too far - on both ends. Oikawa folds his arms as he glares at them, demanding an apology, and Iwaizumi gives his best disapproving gaze, attempting to cross his fins.

Sheepishly, Matsukawa rubs the back of his neck, averting his gaze with lips pressed together in something reminiscent of a pout. Hanamaki huffs, still irritated, but says nothing more. Finally, Matsukawa sighs.

“You’re right. I- I should have helped out a little more, like looking something up online or giving you directions. But I couldn’t just leave the twins to suffer… They’re my baby brothers, they gotta come first.” After another moment, Hanamaki throws his hands up in frustration with a groan of surrender.

“How can I stay mad at you when you bring the sproglets into it?! But, I mean, yeah, you could have helped more. And… I probably shouldn’t have brought a mysterious book from a shop that looked like it temporarily blipped there from another world.” With a hint of jazz hands, Hanamaki rocks back on his heels, a little ashamed of how angry he got when he was initially the reckless one.

A soft breath. An exhale of a laugh. And then, Matsukawa breaks into a chuckle, warm and forgiving.

“You have the _weirdest_ way of phrasing things~.” Hanamaki’s signature lopsided grin reappears.

“Oh, c’mon, how else am I meant to describe it? Seriously, it was like an alternate universe temporarily glitched into ours! I mean, I went back a couple days ago to pick up this _awesome_ dragon statue that was there, and the whole building was gutted!”

“That hinders my intention of questioning the store owner…” Posed with his hand on his chin in deep thought, Oikawa tries - and fails - to come up with anything else. They can’t interrogate the person that sold Hanamaki the book, and they can’t change Iwaizumi back.

All they can do is wait it out.

Sighing heavily, Oikawa crouches down and moves onto his knees, hands resting on the sides of the baking bowl.

“We’re going to have to put you in a plastic bag like Kin-chan said. Just a little longer, then you’ll have a big tank to swim in.” Iwaizumi gives him a deadpan yet sarcastic stare, trying to communicate he’d rather not need a tank at all.

Although he’d much appreciate the extra space. This bowl was _cramped_. He couldn’t even awkwardly wiggle in a full circle without his tailfin brushing against his… nose? Did he even have a nose now? Did fishes have noses?

Oh, this was giving him a headache.

“I brought a little sandwich bag through with the sushi. Doesn’t have holes in, I checked.” That explains the sopping wet plastic thing on the edge of the sushi platter, looking like a discarded jellyfish.

“Thanks, Makki. Here we go, Iwa-chan!” Iwaizumi doesn’t have time to protest before he’s being poured into the bag Hanamaki holds open, Oikawa tipping the bowl. He can feel his heart pounding in his chest as water rushes past his scales and gills, before he’s clumsily plonked back into the water with a splash, so inelegantly that he panics for a moment he’s hit the floor instead.

“Woah, woah! Easy, Iwaizumi! You’re gonna make me drop you!” The plastic bag makes it even harder to hear things, just muffled voices. Matsukawa thinks quickly, cupping his hands underneath the bag and moving them up so that Iwaizumi rests in the palms of his hands, separated only by the plastic bag and a little bit of water. 

The fish stops frantically writing in the bag.

“There we go. I think the splash just disorientated him.” 

“Damn, are fish _really_ that fragile?”

“Oh my god, we’re absolutely not prepared for this. None of us are prepared to look after fish. We just- We can’t do it. We’re going to accidentally kill Iwa-chan before the day is even over!” Oikawa’s little crisis goes ignored by Hanamaki and Matsukawa, shuffling step by step sideways over to the tank, carefully depositing the bag in the top so it slightly floats.

Iwaizumi regards his new position with a critical eye. He can’t exactly swim in this plastic bag, but he can feel the change in temperature through the material. If he wasn’t in the same water he’d been unceremoniously dumped in earlier, the shock of an instant change would have stunned him.

Lucky for him, his friends were pretty good at following Kindaichi’s instructions.

“Alright, give us a wave when you feel comfortable with the temp, and we’ll let you out of the bag.” Iwaizumi waves one fin to demonstrate that he can do it, and Hanamaki smiles as he pokes the bag teasingly. He’s not quick enough to pull back to avoid getting a small nip on the finger.

It doesn’t hurt at all. If anything, it’s funny and cute, disregarding the fact that Iwaizumi just _bit_ him. Hanamaki supposes that, without hands to playfully smack or punch with, biting gently is the only available option for Iwaizumi.

He never hurts them intentionally, he’s just very physical with his affection.

“So… Since it’s Iwaizumi’s birthday, I’m guessing we’re watching Godzilla?” There’s some very happy splashing from behind as Matsukawa grins at his own question, Oikawa barking a laugh.

“What else!? It’s Iwa-chan, after all!” Out of consideration and the kindness of their hearts, the trio rearrange the TV so it’s in a position that Iwaizumi can see it. By the time they’ve rigged up the audio to surround sound, Iwaizumi waves a fin and they release him from the plastic bag. Hanamaki does his stomach the grace of dumping most of the sushi in.

It’s a breath of fresh… Air? Water? … A breath of fresh oxygen to _finally_ have room to move around, and Iwaizumi celebrates by exploring the tank a little bit.

Sure, it’s annoying to be stuck as a fish, but it’s also goddamn _awesome_! He circles the Godzilla figure in the tank, bursts through the stream of bubbles from a treasure chest, and squeezes through the tunnel of the castle decoration.

Underwater plants seem like a gigantic forest to him, swaying as he passes, and the colourful gravel brightens up the whole experience. It’s _amazing_ , like he’s been transported to some kind of fantasy world!

“Oiiii, Iwaizumi~. We’re starting the movie, if you’re finished goofing off~.” Iwaizumi opens his mouth to protest - letting off a stream of bubbles and silence - before realising that yeah, he was _totally_ goofing off.

What can he say? This new world is fun, as long as he knows he can turn back. 

The opening theme to Godzilla snaps him back to reality, and he swims right to the face of the tank, nestling himself in some Pygmy Chain Sword to stay comfortable for the duration of the movie. The others might have popcorn, but he has cucumber maki rolls, and it’s _delicious_.

At times, watching the other three mess around, he feels a little… Isolated. Lonely. 

“Mattsun, don’t fall asleep on me!”

“Shurrup. M’tired. This movie sucks.” He snickers at the ‘TUP’ of Iwaizumi slapping the glass in front of him the best he can with little fins, knowing full well that he would have gotten a nudge in the ribs if Iwaizumi was still human. 

“That doesn’t mean you can sleep on _me_!” 

“.. A'ight then.” With great enthusiasm, Matsukawa flops like a metronome over to his other side, knocking the air out of Hanamaki’s lungs as his head impacts his stomach.

“Seriously, Matsukawa?! Give a man some warning!”

“I’m about to crush you beneath my skull.”

“... _Before_ you do it.”

“Too late now, let me sleep.” Hanamaki makes eye contact with Oikawa and they roll their eyes in unison, but it’s good-natured, and Hanamaki shuffles to get a little more comfortable with being used as a pillow.

At some point, during an epic fight scene, Hanamaki drifts off too, head lolling back onto the cushions and mouth wide open as he snores. Loudly. Iwaizumi _would_ be offended that he’s gone to sleep at one of the best parts, but he knows they really must be tired if they didn’t even say goodnight.

As the credits roll, Oikawa stretches out with a groan, and tugs a blanket up around his shoulders as he walks over to the tank in a half-asleep state. He keeps his voice just above a whisper, soft and fond.

“I don’t know if you can sleep like that, Iwa-chan, but I don’t have the energy to stay up with you. I would if I could, but... “ His jaw stretches with a yawn. Iwaizumi can see the strain under his eyes, how he’s fighting to keep his eyelids open, and the slouch of exhaustion in Oikawa’s posture.

He does a little reassuring backflip, his beautifully curled tailfin brushing against the tank glass. With a huff of amusement, Oikawa sprinkles in what’s left of the sushi platter.

“Happy birthday, Iwa-chan~. Sorry it wasn’t what you expected… What _any_ of us expected, but I hope it went okay. And, well, you’ve got tomorrow’s no-longer-a-surprise-party to look forwards to!” Oikawa laughs again at the wiggle of excitement from his fishy friend, before he covers his mouth with the corner of the blanket, trying to muffle a harder laugh.

“Maybe this is divine retribution for when you compared me to a fish in a book!” Iwaizumi puffs his little fish body out in pride. Finding a fish - the pale chub - with the same name as his best friend had been a _golden_ discovery. 

“Why do you look so proud of yourself, Iwa-chan…?” Oikawa mumbles those words as a rhetorical question, but Iwaizumi answers anyways by swimming in a circle, chasing his curled, fantail as a metaphor for how happy he is.

Oikawa huffs a laugh, fighting back another yawn.

“Sleep well, Iwa-chan. Hopefully you’ll be human again by morning~.” That would be nice, Iwaizumi thinks. Technically, if this ‘spell’ or ‘magic’ or whatever it is is supposed to only last 12 hours, he should be turning back to his original human form by 8-ish in the morning.

_‘Happy birthday to me.’_ , he thinks, watching Oikawa sinks down on the sofa, curling up in the crook of Matsukawa’s legs. Usually, Iwaizumi would be part of that pile. On his birthday, he’d always be at the centre of the cuddle puddle.

He wanted to change back _so bad_.

He wanted to be his normal human self again, swarmed by his friends and surrounded by their warmth, loud jokes and playful wrestling, making fun of them, making fun _with_ them, just…

Just enjoying his birthday…

But instead, he’s here, isolated in a cold tank, swimming around the tank in circles because he’s so, _so_ alone right now. Iwaizumi keeps peering at the clock anxiously, cursing the second hand for moving so slow, cursing the minutes for not passing faster, cursing the hours he has to be stuck like this. 

But time does tick on.

The closer it gets to 8 in the morning, the antsier Iwaizumi gets, swimming back and forth and round in random patterns, even attempting to distract himself by drawing in the gravel. 8:00 comes and goes. 

Exactly 14 minutes later, Iwaizumi starts to feel like he’s tingling all over. It feels like every scale on his body is rippling, and the water is getting heavier, and he _can’t breath-_.

Iwaizumi launches himself out of the tank, surprised that his delicate tailfin could be so strong, and ends up on the floor. For a moment, he’s flopping and suffocating to no avail, but then, just before the second hand on the clock reaches 8:15, he _glows_.

A dripping wet and very naked Iwaizumi shake his head to clear the fuzziness there and looks over himself, sitting cross-legged on his living room floor, before quickly getting up and grabbing some clothes from the ironing pile. They get damp against his wet skin, but he honest couldn’t care less.

Iwaizumi strides over to the sofa, and bellyflops down on top of the cuddle pile, which has become entangled limbs with no end in sight. It’s hard to tell where one person begins and another ends. Oikawa’s groan of pain as his eyes flutter open revela it was his stomach Iwaizumi flopped onto.

“Iwa-chan, what…? Wait! Iwa-chan?!” Oikawa bolts upwards, shouting happily as he lunges at Iwaizumi, hugging him far too tightly for someone who’s just undergone a transformation from fish to human.

“Ow, ow, ow! Let go! That freaking hurts! Oikawa!”

“Heeey, the man of the hour is baaack~. Nice of you to join us, Iwaizumi.” Snorting a laugh, Iwaizumi leans over and punches what he hopes is Matsukawa’s arm.

“Shut the fuck up, you’re partly responsible~.” Hanamaki yawns, loud and obnoxious as he cricks his neck and lifts his head, meeting Iwaizumi practically nose to nose. Iwaizumi grins. Hanamaki forces a nervous laugh.

“G-Give me a 10 second head start?”

“You have 5.” Hanamaki _scrambles_ out of the pile, bolting for upstairs because he knows the bathroom is the only door with a lock on it. Iwaizumi happily settles into the warm spot Hanamaki had previously occupied.

“Iwa-chan, we have to get ready for school~... And you’re wearing mismatched pyjamas.”

“Yeah, I’ll change in a minute. Let me warm up first. That tank was fucking _cold_.” Matsukawa loops an arm around Iwaizumi’s shoulders, pulling him in to ruffle his hair, and continues to support Iwaizumi as he curls into the body heat.

“Bet it was wet too.”

“... It was after I changed back, but… I kinda couldn’t feel the water around me as a fish? Like how we aren’t really aware of the air around us. There was a little more resistance if I moved fast enough, but nothing that really made me feel like I was underwater.”

“Freaky.” Iwaizumi buries his laugh in Matsukawa’s shoulder, tucking his feet underneath Oikawa’s knee. It’s delightfully warm, it’s comfortable, and they’re _here_ with him. Just the physical contact is heart-warming and comforting.

“Do you feel up to practice, Iwa-chan? You’ve been through a lot and-” Oikawa breaks off his sentence at the self-assured smirk he gets from Iwaizumi.

“I’ve never been more ready in my life~.”

“In that case…” Matsukawa stands up, dragging the other two with him.

“We’d better actually get ready.” With a pout, Iwaizumi slides away from the body heat, but then, he spots movement out of the corner of his eye. Hanamaki pokes his head around the door, lulled into a false sense of security by Iwaizumi not chasing him.

This time, Iwaizumi chases him.

As Hanamaki shrieks and runs, Iwaizumi right on his heels, Matsukawa and Oikawa retrieve their uniforms from the night bags they packed, heading to the bathroom to get changed. It takes a few minutes for Hanamaki and Iwaizumi to calm down enough to join them, still shoving at each others shoulders as they brush their teeth.

Only when they’re dressed and about to leave does Iwaizumi stop to look at the tank. It looks… Empty. It’s so beautifully decorated, and although it was a little cold and very lonely, the tank itself was pretty entertaining. 

“Iwaizumi, hurry up! We’re gonna miss the train!” He jogs over to the _genkan_ , slipping on his shoes. Stepping out of the house, he loops his arms up around Matsukawa and Hanamaki’s necks, tugging them down to his chest level.

They’ve already admitted the book wasn’t a good present, and since Iwaizumi has an empty tank...

“Hey, morons. You owe me a fish each~.” The duo roll their eyes in unison but opposite directions as Oikawa cackles at the comedic irony.

“Happy birthday, Iwaizumi.”

“Happy You’re-an-old-man day, Iwaizumi!”

“You’re still insulting me after turning me into a _fish_ , Hanamaki?”

“I mean Happy birthday and you’re one of my best friends and such a great ace.” Iwaizumi chuckles as he releases them, bounding forwards to catch up with Oikawa and shouting over his shoulder;

“You still owe me a fish!”

**Author's Note:**

> I'm so sorry this is literally the best idea I had asfjklnlkfjghfdsjh
> 
> Please kudos/comment!!!


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